A stochastic exposure assessment model to estimate vanadium intake by beef cattle used as sentinels for the South African vanadium mining industry

This paper presents an environmental exposure assessment model for estimating chronic intake of vanadium (a transition metal) by cattle farmed extensively in areas contaminated by vanadium pollutants. The exposure model differs from most other models in several ways: (1) it does not rely heavily on extrapolating information from the point source (e.g. stack height, exit velocity, exit diameter) to the point of exposure. (2) It incorporates the physiological constraints of the species exposed. (3) It takes into account oral as well as inhalation exposure. (4) It addresses terrain, by using measurements at the point of exposure. (5) It accounts for existing background concentrations of pollutants and pollutants from multiple sources. (6) It uses a stochastic process with distribution functions to account for variability in the data over time. Environmental inputs into the model included aerial fall-out sample vanadium (n = 566), unwashed grass sample vanadium (n = 342) and soluble soil sample vanadium (n = 342). Physiological cattle inputs were derived from two cohorts of Brahman-cross sentinel cattle (n = 30). The model provided an estimate of the chronic external exposure dose of vanadium for two separate groups of cattle grazing over a 5-year period (1999–2004) immediately adjacent (median dose = 2.14 mg vanadium/kg body weight/day) and 2 km away (median dose = 1.07 mg/kg/day) from a South African vanadium-processing plant, respectively. The final output of the model is a distribution curve of the probable vanadium intake based on the variability within the inputs over the 5-year period of the study. The model is adaptable enough for application to other transition metals and species (including man), and could be used as an alternative to plume-dispersion modelling.     

Blends of cysteine-containing proteins

Proteins such as keratin, lactalbumin, and gluten can be obtained from agricultural sources. These proteins contain the amino acid cysteine. Cysteine allows for the formation of inter- and intramolecular sulfur-sulfur bonds. It was found that cysteine-containing proteins have varied properties and can be blended together to form materials with the attributes of each polymer. The addition of wheat gluten to other proteins increases the strain to break or "toughness". The addition of lactalbumin increases the modulus and strength of blends. Birefringence shows that lactalbumin contains an added "structure" not found in the other proteins. Permeability studies reveal that one protein may dominate the transport of small molecules through the blend. Scanning electron microscopy shows that blends contain features of each protein and correlate with observed tensile properties.     

Stability and color changes of thermally treated betanin, phyllocactin, and hylocerenin solutions

Thermal degradation of betanin, phyllocactin (malonyl-betanin), and hylocerenin (3' '-hydroxy-3' '-methyl-glutaryl-betanin) solutions isolated from purple pitaya (Hylocereus polyrhizus [Weber] Britton and Rose) was monitored by spectrophotometric and high-performance liquid chromatography-diode array detection (HPLC-DAD) analyses. For betanin and phyllocactin solutions, the color shift upon thermal treatment was found to be nearly identical, while hylocerenin samples exhibited an intelligibly higher chromatic steadiness. Betanin proved to be the most stable individual pigment structure, while the enhanced tinctorial stability of the integral phyllocactin and especially hylocerenin solutions was due to the formation of red degradation products exhibiting improved color retention as opposed to their respective genuine pigments. Individual structure-related stability characteristics can exclusively be assessed by HPLC-DAD analyses and may not be noticed by mere spectrophotometric assessment of color and tinctorial strength.     

Diverting the Colorado River leads to a dramatic life history shift in an endangered marine fish

Diversion of river water has diminished freshwater flow into many estuaries worldwide, yet the effects of these diversions on marine fisheries, many of which depend on estuaries, are largely unexplored. We document the impact of diverting Colorado River flow from the Gulf of California on the life history of a now-endangered marine fish (Totoaba macdonaldi, Sciaenidae). Growth increments in prehistoric (1000–5000 ybp) otoliths document that pre-dam juveniles grew twice as fast and matured 1–5 years earlier than post-dam fish. Oxygen isotopes link these changes to elimination of estuarine habitat. This study provides evidence that river diversion can have a dramatic effect on life history of marine fishes by slowing growth during the juvenile stage, thus delaying maturation. These findings also provide valuable insight into the relative influence of habitat alteration versus fishing pressure on marine fishes.     

Enzyme-linked immunosorbent assay (ELISA) for detection of sulfur-rich protein (SRP) in soybeans (Glycine max L.) and certain other edible plant seeds

As a result of methionine deficiency, legume proteins are considered to be incomplete, and therefore there is a need to explore ways to improve legume protein amino acid balance. Using rabbit anti-soybean sulfur-rich protein (SRP) polyclonal antibodies (pAb), sensitive immunoassays (nanogram sensitivity) were developed. The immunoassays detected SRP in all soybean seeds and soybean-based commercial samples examined. In addition, the presence of pAb cross-reactive proteins was detected in certain dry beans and oilseeds. The cross-reactive proteins were isolated using purified IgG-based immunoaffinity column chromatography. Biochemical analyses including N-terminal amino acid sequencing and amino acid composition indicated that the cross-reactive proteins were comparable to soybean SRP. The cross-reactive proteins contained methionine (1.6-2.4 residues/100 residues) and cysteine (2.4-3.6 residues/100 residues), which satisfies the FAO/WHO recommended pattern for sulfur amino acids in both adults and children (2-5 years old). The results suggest the presence of constitutive SRPs in several dry beans and oilseeds.     

Application of a modified Haug and Lantzsch method for the rapid and accurate photometrical phytate determination in soybean, wheat, and maize meals

A modified version of the Haug and Lantzsch method for rapid photometrical phytate determination was applied for the analysis of phytate in soybean, wheat, and maize meals. In comparison to the original protocol, the amount of the toxic reagent thioglycolic acid is reduced substantially to minimize potential health risks for laboratory personnel. Different extraction conditions for soybean meal were tested, and boiling for at least 30 min was found to be necessary to remove an interfering compound in soybean meal extracts. Phytate contents determined according to the modified Haug and Lantzsch method did not differ from those obtained by measuring total precipitated phosphorus or by sensitive and specific high-performance ion chromatography. Applicability and accuracy of the modified method for phytate analysis in major feed substrates, including soy-based textured vegetable protein, were demonstrated.     

Creosote Contamination in Sediments of the Grey Owl Marina in Prince Albert National Park, Saskatchewan, Canada

The rate at which creosote-treated pilings release polycyclic aromatic hydrocarbons (PAHs) into the environment should diminish with structure age and weathering, and so, it may be assumed that PAH concentrations in the vicinity of old structures (>30 years) may approach background levels. However, this may not be true in cold environments where PAH release and degradation rates are slow and where pilings continue to experience significant physical damage. Moreover, PAHs will remain high in the vicinity of pilings if current and wave action is insufficient to disperse and dilute PAHs over a wider area and/or where PAHs do not become diluted and buried by uncontaminated sediments. This is demonstrated in our investigation of the sediments of the Grey Owl Marina, located in Prince Albert National Park, in central Saskatchewan, Canada. The marina, constructed in the early 1960s, consists of six piers and is protected from strong wave action by a breakwater. PAH concentrations were high in sediments collected under the piers and inside the boat slips, exceeding probable effect levels for several compounds. Various lines of physical and chemical evidence pointed to creosote as being the primary PAH source with a mixture of relatively undegraded and weathered PAHs being present. PAH concentrations decreased rapidly 2 m and further away from the pilings as a result of dilution with increasing dispersal over a broadening area. There was evidence of benthic community impairment, with total abundances negatively correlated with PAH concentrations. According to the Methods for Ranking Contaminated Aquatic Sites on Canadian Federal Properties, areas with the highest hazard scores were under the piers and inside the boat slips, while areas with the lowest hazard scores were >10 m from the pilings. Therefore, remedial actions based on piling and contaminated sediment removal may need to be conducted over only a small area, i.e., within 2 m of the pilings.